The present invention relates to a device for attaching an insertion part, such as an armrest or a hand grip, to a base surface, for example, a surface within the body of a vehicle. In particular, the invention relates to an attachment device of the type in which one part of the attachment is the free end of an armrest or hand grip insert, or the like, and the other part is a clip contained in the wall of the body to which the aforesaid free end is to be secured. The two parts are locked together in a first relative rotative position and are detachable by means of rotating them relative to each other from the locking position.
For armrests and hand grips, it is known to develop the free end of an insert as a part of an attachment device for cooperating with another attachment part, such as an attachment clip contained in the wall of the body to which the insert is to be secured. Known devices of this type can be used when only very little if any padding covers the body wall. In such devices, run-on inclines are formed which, in the manner of a bayonet socket and coupling, pull each attachment part against the other. Such an attachment can be used only in the relatively few vehicles which do not have significant padding. There is still another disadvantage in that manufacturing tolerances and materials tolerances may be so unfavorable that the tightening means (the run-on incline) is not sufficient to achieve a satisfactory wobble-free attachment.
Since it is particularly important in the case of armrests and hand grips to secure them in a wobble-free manner, it is also necessary to adapt the attachment clip so that the inserted attachment device is held securely in all directions. Otherwise, the connection can loosen and the attached parts can separate as a result of the constantly recurring different stresses acting on them in every direction. With an unsuitable design of the inserted attachment part, for instance in the case of a part having a rectangular cross-section, the attachment part may break after a period of time due to the stresses on it in use.
Interlocking structures, especially for attaching armrests to a body, are known. Such structures are known, however, only in attachment devices which include an insert whose cross-section is, for instance, circular or rectangular. In each of these cases, the interlocking structure is associated with the free outer edge of the armrest.
In addition to the requirement of maintaining a secure and permanent attachment after installation, the attachment parts must be such that they can be attached without damage to them or to the neighboring regions of the body to which they are secured. The aforementioned cross-sectional shapes cannot be received in an even approximately form-locked manner if these requirements are to be met. Form-locking, however, is essential for wobble-free attachment. If only for this reason, the known devices employing interlocking structures could not pass beyond the preliminary experimental stage.